Hi Jennifer, clear drops can still be brought to supersaturation by:
-transfer to wells with lower vapour pressure: exchange or add LiCl or other concentrated salt solutions in the reservoir -temperature gradient: place trays on ice/cold surface while hanging drops are at higher temperature, this will draw more water out of the drops. -transient supersaturation might be sufficient to trigger nucleation and subsequent crystal growth: slightly open wells for a few minutes (or longer) and close again. -protein solubility also can strongly depend on temperature: move to 4°C etc. ... and why not using the 100mg/ml stock or concentrate even more? Good luck, Clemens Quoting Jens-Christian Navarro Poulsen <[EMAIL PROTECTED]>:
Hi Jennifer I just want to draw your attention the following paper regarding methylation of Lysines, which reduces the solubility of their test proteins. Walter <http://www.ncbi.nlm.nih.gov/pubmed/17098187?ordinalpos=7&itool=EntrezSystem 2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum> TS, Meier C, Assenberg R, Au KF, Ren J, Verma A, Nettleship JE, Owens RJ, Stuart DI, Grimes JM. <http://www.ncbi.nlm.nih.gov/pubmed/17098187?ordinalpos=7&itool=EntrezSystem 2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum> Abstract Lysine methylation as a routine rescue strategy for protein crystallization. Structure. 2006 Nov;14(11):1617-22. PMID: 17098187 [PubMed - indexed for MEDLINE] Best regards, Jens-Christian Navarro Poulsen Dept of Chemistry, KU _____ From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Jennifer Han-Chun Tsai Sent: 13. maj 2008 18:17 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] problem of crystallization Hi, This topic is not related to CCP4. I am having problem of crystallizing one protein. It's a pretty small protein with size around 15kDa. I have stock concentration around 100mg/mL. Crystallization plates I set up are with concentration of 10mg/mL, 30mg/mL and 50mg/mL. All the plates had been set up at least one week. Only around 5 wells per plate or less formed precipitation. The rest of wells are pretty clear still. Is there any suggestion for reducing protein solubility or increasing the chance of getting crystals? Thanks for your time, Jennifer
